Messages in this thread | | | Date | Mon, 27 Jul 2020 17:05:15 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH -next] arm64: Export __cpu_logical_map |
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On Sun, Jul 26, 2020 at 05:16:27PM +0530, Sumit Gupta wrote: > > > > ERROR: modpost: "__cpu_logical_map" [drivers/cpufreq/tegra194-cpufreq.ko] undefined! > > > > > > > > ARM64 tegra194-cpufreq driver use cpu_logical_map, export > > > > __cpu_logical_map to fix build issue. > > > > > > > > I wonder why like other instances in the drivers, the mpidr is not get > > directly from the cpu. The cpufreq_driver->init call happens when the cpu > > is being brought online and is executed on the required cpu IIUC. > > > Yes, this occurs during hotplug case. > But in the case of system boot, 'cpufreq_driver->init' is called later > during cpufreq platform driver's probe. The value of CPU in 'policy->cpu' > can be different from the current CPU. That's why read_cpuid_mpidr() can't > be used. >
Fair enough, why not do cross call like in set_target ? Since it is one-off in init, I don't see any issue when you are doing it runtime for set_target.
> > read_cpuid_mpidr() is inline and avoids having to export the logical_cpu_map. > > Though we may not add physical hotplug anytime soon, less dependency > > on this cpu_logical_map is better given that we can resolve this without > > the need to access the map. > >
To be honest, we have tried to remove all the dependency on cluster id in generic code as it is not well defined. This one is tegra specific driver so should be fine. But I am still bit nervous to export cpu_logical_map as we have no clue what that would mean for physical hotplug.
-- Regards, Sudeep
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